<template>
  <div class='xtx-carousel' @mouseenter="stop()" @mouseleave="start()">
      <!-- 轮播图图片容器 -->
    <ul class="carousel-body">
        <!-- fade样式  显示图片 -->
        <!-- :class="{fade:index===i} 默认显示 -->
      <li class="carousel-item" v-for="(item,i) in sliders" :key="i" :class="{fade:index===i} " >
        <!-- 图片 -->
        <RouterLink to="/" v-if="item.imgUrl">
          <img :src="item.imgUrl" alt="">
        </RouterLink>
        <!-- 商品列表 item=[goods1,goods2...] -->
        <div v-else class="slider">
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img :src="goods.picture" alt="">
            <p class="name ellipsis">{{goods.name}}</p>
            <p class="price">&yen;{{goods.price}}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
    <!-- 上一张 -->
    <a @click="toggle(-1)" href="javascript:;" class="carousel-btn prev"><i class="iconfont icon-angle-left"></i></a>
    <!-- 下一张 -->
    <a @click="toggle(1)" href="javascript:;" class="carousel-btn next"><i class="iconfont icon-angle-right"></i></a>
    <!-- 点点点 -->
    <div class="carousel-indicator">
        <!-- active 激活点 -->
      <span @click='index = i' v-for="(item,i) in sliders" :key="i" :class="{active:index===i}"></span>
    </div>
  </div>
</template>

<script>
import { watch, ref, onUnmounted } from "vue";
export default {
  name: "XtxCarousel",
  props: {
    // 接收轮播图数据
    sliders: {
      type: Array,
      default: () => [],
    },
    // 是否自动轮播
    autoPlay: {
      type: Boolean,
      dafault: false,
    },
    // 轮播间隔时间
    duration: {
      type: Number,
      default: 3000,
    },
  },
  setup(props) {
    // 控制显示图片的索引
    const index = ref(0);

    //  1.自动轮播逻辑
    let timer = null;
    const autoPlayFn = () => {
      // 防止定时器重复添加
      clearInterval(timer);
      // 自动播放 每隔多久切换索引
      timer = setInterval(() => {
        index.value++;
        if (index.value >= props.sliders.length) {
          index.value = 0;
        }
      }, props.duration);
    };
    // 调用的这个函数时机  需要监听sliders的数据变化 判断如果有数据且autoPlay是true（有图片数据 确认自动播放）
    watch(
      () => props.sliders,
      (newVal) => {
        if (newVal.length && props.autoPlay) {
          autoPlayFn();
        }
      },
      { immediate: true }
    );

    // 2.鼠标进入暂停 离开开启自动播放（有条件）
    const stop = () => {
      if (timer) clearInterval(timer);
    };
    const start = () => {
      if (props.sliders.length && props.autoPlay) {
        autoPlayFn();
      }
    };

    // 3.点击点点可以切换 上一张 下一张
    const toggle = (step) => {
      // 将要改变的数组索引
      const newIndex = index.value + step;
      // 超出的情况 太大了
      if (newIndex > props.sliders.length - 1) {
        index.value = 0;
        return;
      }
      // 太小了
      if (newIndex < 0) {
        index.value = props.sliders.length - 1;
        return;
      }
      // 正常
      index.value = newIndex;
    };

    // 4.组件卸载时 清除定时器
    onUnmounted(() => {
      clearInterval(timer);
    });

    return { index, stop, start, toggle };
  },
};
</script>
<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
// 轮播商品
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px!important;
      height: 230px!important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>
